Oklahoma's attorney general agreed Thursday to a six-month stay of execution for a death row inmate while an investigation is conducted into last week's botched lethal injection.

Attorney General Scott Pruitt's office filed court documents Thursday saying it wouldn't object to a 180-day stay of execution being sought by attorneys for inmate Charles Warner while the investigation is underway.

Warner was scheduled for execution on the same night last week as Clayton Lockett in what would have been the state's first double execution since 1937. But Lockett's vein collapsed during his lethal injection, prompting prison officials to halt the execution. He later died of a heart attack.

Gov. Mary Fallin then issued a two-week stay of execution for Warner, but his attorneys asked for a six month delay. Pruitt's office agreed in a motion filed with the Oklahoma Court of Criminal Appeals, and if the court agrees, Warner's execution would be postponed until Nov. 13.

The news comes just days after Clayton Lockett's botched execution for the brutal murder of a 19-year-old woman. The execution lasted 43 minutes. While strapped to the gurney, Lockett reportedly writhed in pain. Although officials eventually suspended the execution, he died of cardiac arrest shortly thereafter.

Lockett's execution came after a failed legal challenge to Oklahoma's secrecy as to the identity of the pharmacy providing the drug cocktail for his execution. Oklahoma is one of several states that protects the anonymity of these sources claiming such measures are necessary to protect the suppliers from retaliation by anti-death penalty advocates. This protection has come under increasing scrutiny as traditional European suppliers of sodium thiopental, the drug formerly employed in executions, have ceased exporting the drug to the U.S.

Several states now employ drug cocktails provided by compounding pharmacies. Lockett's execution, for example, began with an extraordinarily large dose of the sedative midazolam. He then received the paralytic pancuronium bromide, followed by potassium chloride to stop his heart.